[an error occurred while processing this directive] ZEPHYR Magazine
                              T H E
  
                           Z E P H Y R
  
                  __     M A G A Z I N E
                 {__]++++++++++++++++++++++++++[] 
                 Issue #44                8-16-87
 
            A weekly electronic magazine for users of 
                        THE ZEPHYR II BBS 
                    (Mesa, AZ - 602-894-6526)
                owned and operated by T. H. Smith
 
                    Editor - Gene B. Williams 
 
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                            (c) 1987
  
THIS ISSUE:

   Over the last week several things have come up on the 
public board. I figured, why not turn some of the answers 
into a Zephyr Magazine article.
   There was the question of sound versus radio and light.
That leads into the relationships and characteristics. That 
brought us to a beginning discussion on light speed and 
relativity.
   The issue is going to ramble a bit, but it's all connected.


              SOUND, LIGHT, ANTENNAS AND RELATIVITY

   It's not that difficult to understand, really. 
   Right off, you have to know that sound and electromagnetic 
energy are two completely different things. It has nothing 
to do with frequency.
   To exaggerate, a particular magazine comes once each month. 
A newspaper comes once each day. The newspaper has a higher 
frequency. But even if you keep getting something more often - 
it's frequency increases - it's still printed matter. It 
doesn't suddenly become something different.
   Now think of the speed of sound. A 20 Hz signal moves at 
the same rate as a 20,000 Hz signal which moves at the same 
rate of a 200,000 Hz signal (assuming that the media is the 
same). 
   That speed is somewhere around 1100 feet per second, depending 
on what the sound is traveling through. It's faster in a solid 
than in air, for example. It also varies with humidity, temperature, 
pressure, etc., but that variance is never by a whole lot. 
   Light books along at roughly 186,000 miles per second. This 
also varies. It slows slightly when traveling through a more 
dense media, and can be slowed or bent with a magnetic field. 
But again, the variance is negligible.

   Your ears begin working at about 20 Hz. You hear a deep 
bass. Below this, the sound is still there, but your ears 
can't detect it. As the frequency goes up, so does the tone, 
until somewhere around 20,000 Hz you can't hear it. (That 
range varies from person to person, sex to sex, and age to 
age, by the way. A 16-year-old girl might be capable of hearing 
that entire range, while a 37-year-old fart like me with ear 
damage will be lucky to pick up a range of 100 Hz to 15,000.)
   The speed remains the same throughout.
   Say there is a guy with a guitar several hundred feet away 
from you. Better yet, say he's 1100 feet away and has a big 
amplifier. He twangs across an entire chord. From your spot 
you'll see his hand move across the strings, and one second 
later you'll hear the chord. 
   You'll hear all of it, all at the same time. It won't be 
like hearing the higher notes first, then the lower notes. All 
the tones reach your ears at the same time because they all 
travel at the same speed. The higher tones - higher frequencies 
aren't moving faster. They're just higher in frequency.
   The same is true of light and radio waves (which aren't waves, 
by the way, but that's another subject). Frequency has nothing 
to do with speed.
   So, you turn the knob on your fancy sound generator and keep 
increasing the frequency. At 20,000 Hz you can't hear it any 
longer. Your dog can, but you can't. At 40,000 Hz even the dog 
won't be able to hear it. You're in the ultrasonic range.
   Nothing magical has happened. It's just that your ears can 
no longer detect the sound. It hasn't increased in speed - just 
in frequency. Keep increasing the frequency as far as you 
like and it will still be the same. 
   It travels along at about 1100 feet per second at 20 Hz, and 
at 1100 feet per second at 20,000 Hz. There is no point - magical 
or otherwise - where that sound suddenly speeds up from that 
1100 fps to 186,000 miles per second.
   Sound requires a physical medium. It works by compression 
and rarifaction, sorta like /// / /  /  / ////// /  /  / ////; 
kinda like clapping your hands. Without a physical medium to 
compress, sound won't go anywhere. 
   Take a best speaker in the world and take it into space - a 
dead vacuum. Now feed it a signal through a 1000 watt amplifier. 
With your ear just an inch from the speaker, you still won't 
hear anything. Give it 100,000 watts and you still won't hear 
anything. No medium of travel, so no sound. (Of course, if you 
try the experiment you won't be around to describe the results. 
You need air as much as sound does.)

   Electromagnetic waves don't need a medium. In a sense, they 
are their own medium.
   To date, no one has come up with a 100% valid explanation 
for electromagnetic waves. They're not waves, but act as though 
they are at times. At other times they act like physical 
particles. They exist - yet they don't.
   The present description involves bundles of energy - quantums - 
with no physical existence. This allows them to fit in with the 
theories of relativity and also serves to accurately and 
mathematically describe what is otherwise a contradiction.
   As with sound, electromagnetic waves can be of virtually any 
frequency. The frequency has nothing to do with the speed. That's 
more or less a constant (depending on conditions).
   Divisions in the spectrum are based on characteristics, uses, 
and convenience. Microwaves are radio waves, but of a higher 
frequency, with some different characteristics and different 
uses. Radar is a microwave, which is a radio wave. Go just a 
touch higher and you have light, including the narrow band of 
the visible spectrum.
   At the bottom is infrared. You can't see it, but the 
characteristics of light are all there. Then comes red and 
on up through the visible spectrum to violet, then out of 
the visible range again and into ultraviolet. It's still 
light.

   Subsonics, like all sound, can set up a vibration in objects 
that are struck by the sound waves. At certain frequencies and 
at sufficient power, the rough vibrations can cause physical 
objects to crumble. Subsonics have been used experimentally as 
a destructive force.
   Ultrasonics also cause a vibration. Brittle objects can be 
made to shatter - right out of a Memorex commercial, huh? The 
high rate of vibration, with sufficient power, can cause the 
object to heat. This is somewhat like the action of a microwave 
oven, but not really. A more common use of ultrasonics is as 
a means of cleaning things such as jewelry. The jewelry gets 
vibrated, and the dirt is almost literally "shaken off" (although 
usually some kind of cleaning fluid is used to help the process 
so that not as much power is needed, which in turn reduces the 
risk of damage to the item being cleaned).
   Then there's resonance. 
   Set up a hollow box with a tuning fork mounted on top. Aim 
the opening of the box toward an identical box with an identical 
tuning fork. Strike the first tuning fork. It will set up 
sound vibrations which resonate inside the first box, move across 
to the second, which also resonates, which causes a vibration 
that in turn makes the second tuning fork ring.
   Physical objects, solid or hollow, have characteristic 
resonant ranges. That again is how they shatter the glass in 
those Memorex commercials.
   Rub your finger around the top of a fine quality glass. The 
glass will ring with its resonant frequency. The glass is 
physically vibrating to make that sound. If you induce that 
frequency into the glass from an outside source of sufficient 
strength, the glass again will vibrate. If it vibrates strongly 
enough, it will break.

   What confuses some people is that those same things are found 
in electromagnetic waves. Different frequencies have different 
physical effects; and there is resonance. But, the WAY it 
happens is quite different. The names used to describe the effects 
are the same simply because the effects are much the same.
   In energy waves there is a relationship between frequency and 
wavelength. Since speed is a constant (under the same conditions), 
one frequency moves at exactly the same speed as signals of any 
other frequency.
   Electromagnetic waves appear as sine waves - like smooth and 
even waves on the water. 
    
     .  		.a .     	    . b.		  
 	.	      .	     .	 	  .	 .
--------------------.----------c--------.----------d---------.-----
	   .      .             .      .	     .      .
	     .  .		  .e .                 .f .


   Well, something like that. 
   Between a and b, between c and d, between e and f - that's 
one cycle. The number of cycles per second is the frequency, 
measured in hertz. 
   The physical distance covered by one cycle is the wavelength. 
   Move your hand up and down as you swing your arm from left to 
right. In other words, make a sine wave in the air. The distance 
between when you hand reaches the top once and reaches the top 
again is the wavelength. 
   Now move your hand up and down more rapidly, while keeping 
the speed of your arm motion the same. You'll see that the 
wavelength gets shorter.

    
     .  	.a     	    .b		. .  
       .      .    . 	  .    .       .   .        .
-------------.------c----.------d-----.-----.------. 
        .   .        .  . 	 .   .       .    .
         . .	      .e          .f           . .


   So, as frequency goes up, wavelength goes down in an inversely 
proportionate ratio. Speed remains constant and a part of the 
whole formula.

   Wavelength = speed of electromagnetic energy/frequency, 

   or more simply

   Wavelength = c/f

   By using this formula, you can design an antenna for any 
given frequency. The "c" is a constant - 186,000 or 300,000, 
depending on whether you're using the English or the metric 
system. 
   To successfully use the English version, you have to convert 
the miles into feet. Lots of fun! The metric version is easier.

   Say you want to build an antenna for picking up a radio station 
that broadcasts on 700 KHz (700,000 cycles per second). The 
antenna is built around the wavelength because of electromagnetic 
resonance. 

   Wavelength = 300,000,000 meters / 700,000 cps = 428.6 meters
(about 1400 feet)

   The wavelength of KZZP (104.7 MHz on your dial) comes out as:

   W = 300,000,000 / 104,700,000 = 2.9 meters
(a little over 9 feet)

   The wavelength of a satellite channel on 4.7 GHZ comes out as:

   W = 300,000,000 / 4,700,000,000 = .064 meters = 6.4 centimeters
(roughly 2 1/4 inches)

   The basic antenna is a halfwave dipole, which means that the 
total antenna is 1/2 the total wavelength, with that antenna being 
divided into two equal parts. 
   Like this (sorta):

________________________________  ______________________________
                               / /
                               
   The whole thing is 1/2 of a wavelength, with each leg being 
1/4 of a wavelength.
   So, a simple dipole for 700 KHz would be 214.3 meters long, 
with each quarter-wave leg being 107.15 meters long. 
   The dipole for KZZP would be 1.45 meters long, with the legs 
each being .725 meters in length.
   That satellite dipole antenna for 4.7 GHz would be 3.2 cm 
overall, and 1.6 cm per leg.

   One side of the antenna serves as a positive leg, while the 
other works as a ground. One leg *can* be a literal ground, leaving 
the quarter-wave. Quite a few antennas are built around this 
principle. When you see a "whip" antenna on a car, you can bet 
that it's something like this, with the car itself acting as the 
ground side. You can also estimate the frequency by looking at 
the length of the antenna you can see. 
   From there it starts getting complicated. For example, there 
are 1/4 wave antennas. There are also 1/8 wave, 5/8ths wave, 
and antennas that are electrically "loaded" with resonant 
combinations of coils and capacitors that make the radio transmitter 
or receiver "think" it has a resonant antenna out there.
   Especially with higher frequencies, even the material used 
to build the antenna comes into play. Different materials conduct 
electricity differently. Copper is more efficient than aluminum, 
for example. It conducts better. Gold is better yet - although 
you're unlikely to see *anyone* make an antenna out of gold. (Too 
expensive and too soft.)
   For better efficiency, directors and reflectors can be added, 
thus creating a "beam" antenna. Or you can "phase" several antennas 
together.
   Then there's the standing wave ratio - SWR - of an antenna. 
Because of the positive/negative nature of electricity, and the 
nature of alternating current, the signal is going out and coming 
in (reflected) at the same time. This creates an electrical 
standing wave on the antenna. 
   The prime would be a ratio of 1:1 - equal in both directions. 
The higher the ratio, the less efficient the antenna. A SWR of 
1:3 is okay but not very good. A SWR of 1:100 or 1:1000 means 
that you may not be able to pick up very much signal.
   It's worse when it comes to transmission. A high SWR for a 
receiver just means that you won't pick up as much. A high SWR 
to a transmitter means that the transmitter has to work harder to 
force the signal out. It can even mean that the transmitter will 
burn out - and possibly the antenna - or its parts - as well.
   Even the cable comes into play. Shielded or not, it's still 
conductive wiring and plays an active part in the overall system. 

   What it comes down to is that the basics are simple, but the 
details require a LOT of time and research. You won't pick them 
up from a single short article.

   And finally there is the speed of light and relativity.
   Same thing. The basics are pretty easy. To get deeper into 
it requires some heavy study and a LOT of time.
   According to the theory, as physical matter increases in 
speed, it becomes physically smaller while also becoming 
physically more massive. (Meanwhile, relative time for that 
object slows down.) 
   Relative to itself, nothing has changed. If you're on a 
mile long spaceship zooming along at near the speed of light, 
your ship (and you) will have shrunk in size while it has 
increased in mass. To you on board, everything is exactly the 
same. 
   The increase in mass is very real, and has been measured in 
the laboratory. Same for the decrease in size and the decrease 
in relative time. 
   It takes a certain amount of energy to accelerate an object 
of given mass to a given speed. It will take more energy to 
accelerate a more massive object. 
   As the object approaches the speed of light, its mass 
approaches infinity, which means that more and more energy is 
needed for further acceleration. It eventually reaches a point, 
just short of the speed of light, where the mass is so close 
to being infinitely large that an infinitely large force is 
needed to push it faster. To actually REACH light speed, where 
the mass becomes infinite, an infinite amount of energy is 
needed.
   That's an over simplification but you see the problem.
   The only way to travel at light speed is to find a way to 
get the physical object to not be a physical object. That's 
what stimulated the idea of converting something physical into 
pure energy, transmitting that energy, and then reassembling 
it on the other end.
   We're a long LONG way from something like that, if we ever 
discover how to do it (other than in a special effects 
department). Think of some of the problems involved. Converting 
mass to energy is already possible. Convert less than 1% of 
mass into energy and you've got . . . an atomic bomb. To 
convert all the mass you're facing the e=mc2 formula, which 
shows that if you could convert a paper clip totally into 
energy, you'd have enough to power all of Phoenix for some 
time to come.
   Imagine the energy that has to be controlled in the conversion 
of a 200 pound man - or a 200,000 ton ship if you want life 
support to go along with you.
   All that energy has to be controlled. So for a moment think 
of the chamber that would be needed to hold in and control 
all the force of an atomic bomb, when just a tiny fraction of 
about a pound of mass is converted.
   And even if we do overcome all of that, it won't do all 
that much good for space exploration.
   First, there would still be the time to get the receiving 
end of the device at the target. Without the receiver, the 
problem of transmitting and reassembling something physical 
becomes even more difficult. And of course, without a 
transmitter, you're stuck anyway. You can't get back.
   And even without a receiving station, there is time. The 
speed of energy might seem fast, but it's a snail's crawl 
in space. The nearest star system outside our own is more 
than 4 years away at the speed of light. There are only a 
handful of star systems within 100 years of earth even if 
you're travelling at the speed of light.
   100 years there - 100 years to get back (if you can). To 
cross just our relatively insignificant galaxy would take 
100,000 years at the speed of light.
   So, you start with a virtually impossible assumption and 
end up with an absolutely impossible situation.

   Faster than light travel? Now you have a new set of 
problems that are even tougher. There are some weak 
indications of particles that travel faster than light, but 
the evidence so far is not conclusive by a long shot. Even 
if it turns out to be, the same indicators say that those 
particles are trapped on their side of the barrier every 
bit as much as we're trapped on our side.
   Space warps? Those are the invention of science fiction 
writers who needed SOME way to get their characters across 
the impossible. There is scientific basis for it except in 
the imagination. Again, it's just great for the special 
effects department, but inappropriate in the real universe.
(In other words, just because you want something to exist 
doesn't mean that it will exist.)
   Crossing other dimensions? Same thing.
   
   "We don't know enough" is a fine excuse for believing. It's 
true, in essence. I hope I'm crediting this right - I think 
it was Jim Lippard who said something along the lines of, "Sure 
we've been wrong in the past, but think about all the times 
we've been right."
   Einstein's ideas have been shown to be remarkably accurate. 
When tested in the labs, the predictions are shown to be 
true in virtually all cases. Modifications to the theories of 
relativity he developed over a half-century ago have all been 
rather minor, and mostly done in an effort to create the 
so-called Unified Theory to tie everything in together.
   It's always possible that one day in the far distant future, 
assuming our planet lasts that long, someone will discover a 
way to meet or exceed the speed of light. It's more likely that 
what will be discovered is that Einstein was essentially right 
all along.
   There was the "discovery" of gravity. Newton was essentially 
correct. Modifications have been needed, but he did a remarkable 
job under the circumstances. As time goes by, the theories of 
today will be further modified by new evidence. However, it's 
extremely unlikely that anyone will discover that the laws of 
gravitation are all wrong.
   Most of the common excuses and statements have been already 
said over on the Public board. Things like how we used to think 
it was impossible to fly, or impossible to reach the moon. But 
there is a major difference between all of those and the 
present discussion.
   First, saying that we thought flight was impossible is 
misleading. Quite a few of the best known scientists all through 
our past believed it possible, and inevitable. Back in ancient 
Greece there was the mistaken idea that it would be done 
with wings and feathers. DaVinci, and others, took it farther, 
believing all along that it was just a matter of time. By 
the time the Wright Brothers came along, the idea of powered 
flight was already accepted. 
   Sure there were some who didn't believe it possible. More 
knew that it was, and that the laws of physics fully supported 
their ideas.
   Same for flight to the moon, and a vast number of other ideas.
Check it out thoroughly and you'll find that most of those who 
objected weren't exactly well known scientists. Often they 
were well known deacons (or whatever) of the church. Other 
times they were politicians. Mostly they were just narrow 
minded people who really didn't understand science and who 
couldn't be bothered to take the time to learn, or refused to 
because new ideas and new facts interfered with their own 
preset nonsense. 
   "It's against the laws of God for man to fly - therefore 
flight is impossible."
   "God created a perfect universe - therefore any idea that 
the earth isn't at the center, or that planetary motion isn't 
done in a perfect circle is heresy."


   Tis the stuff dreams are made of. 
   Cranking up the frequency of sound until it becomes light. 
Or cranking down the frequency of light until you can hear it. 
Travelling physically at the speed of light. Or converting 
mass to energy, making the trip, and changing back into mass 
again.
   Dreams. Unsubstantiated and unsupported.
   It's frustrating, but that's just the way it is.
   "We don't know enough." 
   "Yup. That's true."
   "And maybe some day we'll find out how to travel faster than 
light."
   "Yup. Possible. But highly unlikely."

   We have some very scientifically people on the board here. 
This next week should be rather interesting!


Until Next Time

   I have a spare issue ready. And there's the "Chris for 
Governor" story; and a story written by one of the other 
users that is nearly ready to go. 
   Now I have to decide which should go up next. And who knows, 
maybe something elsewhere on Zephyr - or here - will stimulate 
something totally different from what I already have in mind.
   You'll just to wait and see.

   Meanwhile, there's a lot of information in this week's 
issue on a variety of related subjects. Take your pick and 
have at it.
   Wanna talk about becoming a ham radio operator? Fine. I'll 
be glad to answer your questions. Neighborhood Pro is also a 
ham operator, as is Dave Kelly; Chris Mitchell was.
   Maybe you're trying to figure out how to design an antenna 
so you can pick some radio station out of Tucson. (I did that 
a few years ago when Prarie Home Companion was available only 
from the Tucson NPR station.)
   Probably most popular will be the things on space travel and 
light speed and relativity, which is also fine. I *do* request 
(but not demand) that you take a bit of time to do some studies 
on your own so you have some idea of what you're saying. You 
can just bet that if you put your foot in your mouth, someone 
is going to help you shove it down to the kneecap. (We have some 
VERY smart people here! Trying to tackle someone like Jim 
Lippard or even myself on a scientific matter when you yourself 
have no scientific backing is kinda like jumping off a cliff and 
expecting to flap your arms and fly away safe.)
   So the caution is for your own benefit.
   Say whatever you wish, but don't be surprised - or offended - 
when some knowledgeable people toss it right back at you.



Zephyr Magazine is © Gene Williams. All rights reserved.